An adjustable rotary insert bit tool holder is known in the art as disclosed in U.S. Pat. No. 3,882,582, having a peripheral recess in which the bit is clamped with a wedge and a lock screw directed inwardly of the recess forcing the wedge frictionally against one side of the recess. A lifting jack engages under the bit and is adjusted outwardly of the recess by a screw threaded through the jack and against the bottom of the recess.
Another relevant prior art adjustable insert seat and wedge assembly is disclosed in U. S. Pat. No. 4,318,647. In such disclosure, a boring cutter which is adapted to be rotated about its central axis includes at least one insert pocket having opposed parallel leading and trailing walls, as well as a bottom wall. An insert seat of generally L-shaped configuration is provided, with the leading surface of the insert seat being in abutting relationship with the leading wall of the pocket. The opposed trailing surface of the insert seat includes both a leading and rear locating support surface adapted to receive an indexable cutting insert. A wedge is receivable between the rear surface of the cutting insert and the trailing wall of the pocket. The radial position of both the insert seat and the wedge, relative to the central axis of the boring cutter is adjustable. By this arrangement, the radial position of the cutting insert may be varied to thereby adjust the effective outer diameter of the boring cutter. In addition, the amount of overhang, or the difference in the radial position between the cutting insert and the wedge, remains constant thereby maintaining the structural support for the cutting edge of the insert